This invention relates generally to lock monitoring systems, and more particularly to a lock monitoring system for determining the position of a lock cylinder in a mortise lock assembly.
There are a number of different ways that users have attempted to make locks “tamper proof” using lock monitoring systems. Some systems incorporate alarms associated with the insertion of an incorrect key into a lock cylinder. The alarms cooperate with the inner workings of the lock cylinder, such as the pin/tumbler assembly, to signal when there is tampering with the pin/tumbler assembly within the cylinder. The alarms provide an audio or visual indication, or trigger a locking mechanism, when the pins within the lock cylinder are improperly manipulated.
Other conventional lock monitoring systems signal an alarm when the lock assembly is being pried or jimmied or otherwise forcibly engaged. The lock assembly includes sensors and, when there is an attempt to pry or damage the lock assembly or surrounding frame, the sensors signal an alarm.
Lock monitoring systems do not typically address the position of the lock cylinder. In a mortise lock assembly, the lock cylinder rotates a cam to place the lock in a locked condition or an unlocked condition, as well as to retract a latch or a deadbolt to a retracted position. Therefore, the rotation of the lock cylinder and cam is usually an indication of either ingress or egress through the door.
Mortise lock assemblies vary in size and depth. Similarly, lock cylinders also vary in size and depth, as does the shape and design of the cam. Thus, it is difficult to provide a lock monitoring system for a lock cylinder that will work effectively with all mortise lock assemblies and lock cylinders.
For the foregoing reasons, there is a need for a lock monitoring system that monitors the position of the lock cylinder. The new lock monitoring system should signal an alarm, or be integrated into an alarm system where rotation of the lock cylinder may be monitored for security reasons. Ideally, the new lock monitoring system should be applicable to new and existing mortise lock assemblies, especially in a retrofit application.